1. Field of the Invention
This invention relates to an optical head and an image recording apparatus including the same for recording an image on a recording medium using laser light.
2. Description of the Prior Art
An image recording apparatus comprising an optical head including a multi-mode laser diode for emitting a laser beam, a collimating lens system for collimating the laser beam, an objective lens for focusing the collimated laser beam on a recording medium to form a laser beam spot on the recording medium, such as a heat sublimation ink film or a heat melting ink film, and a drive circuit for driving the laser diode in accordance with a video signal to reproduce an image on the recording medium and a scanning mechanism for effecting a scanning operation is known. Another prior art image recording apparatus having a plurality of multi-mode laser diodes for emitting a plurality of laser beams to form a plurality of laser spots, namely, a plurality of pixels, respectively through a similar optical system and through a similar scanning operation is also known.
In these prior art image recording apparatus, because a higher resolution and a higher recording speed are required, a power of the laser diode is increased up to 500 mW. In such a condition, a width of the laser light emitting portion becomes more than 50 .mu.m. Therefore, it is difficult to obtain a small spot on a recording medium, having a high power, for forming each pixel through a general optical system with the multi-mode laser diode.